The idiotype of the immunoglobulin on a given B cell malignancy (Id) can serve as a clonal marker, and our previous studies in lymphoma patients have demonstrated that autologous Id protein can be formulated into an immunogenic tumor specific antigen. This was a single patient protocol designed to test the hypothesis that antigen specific immunity can be transferred from bone marrow transplant donor to recipient. We immunized an HLA-matched sibling marrow donor with myeloma IgG, isolated from the plasma of the BMT recipient, conjugated to an immunogenic carrier protein, and emulsified in an adjuvant. The primary objective of this study was to induce myeloma idiotype specific immunity in the marrow donor and to evaluate the transfer of myeloma idiotype-specific immunity to the patient following allogeneic bone marrow transplantation. Donor immunization was performed at the BRMP. The allogeneic bone marrow transplantation procedure was performed at the Fred Hutchinson Cancer Research Center in Seattle.